Studying both F3 and F7 simultaneously or separate?

Hello Sir, I have recently completed F2 just over a week ago and have already passed F1. I have now just began studying F3 after acquiring the notes however, i do intend to enter for an exam in the September session. i have opted to combine my study of f3 alongside f7 as they have such a strong relation. also i have a moderate amount of knowledge regarding the f3 syllabus and and also the depth of the topics. Would it be optimal to complete f3 as a standalone subject and after the CBE initiate study of F7 or would it be counter productive to make this concoction? If so which paper would be a more prudent decision for the September sitting? Many thanks, Mij